Brake for motor-driven vehicles



Dec., l?, 1935. f A, @ADAMS Y 2,()24,137

.BRAKE FOR MOTOR DHIVENA VEHICLES Filed sepan?, 193s '9, 56 33 13 E i 8 36 WITm-:ssaszmvENTo/;

Patented Dec. 17, 1935 UNITED .STATES PATENT OFFICE 6 Claims.

My invention relates to brakes for motor-driven vehicles, and its principal object is to provide a brake for the purpose set forth which is capable of exerting a more powerful braking torque,

having regard to its size, than is possible with such brakes ,as at present constructed.

Another object of my said invention is to provide a brake of the character referred to in which the frictional elements are brought into engagement throughout their entire periphery with the drum surfaces, so that they are capable of with-' standing much higher working pressure without over-heating, and are also capable of being operated over long periods without the necessity of adjustment or repair.

,A further object of my said invention is to provide a brake operating mechanism in which the internal forces are completely balanced and in which frictional losses are reduced to a minimum, so that a much more powerful braking effort is obtainable with less work on the part of the operator.

With these and other objects in view, the invention consists in the improved construction,

arrangement, and combination of parts which will be hereinafter fully described, reference being had to the accompanying drawing, which i1- lustrates a preferred embodiment thereof, in which drawing- Figure 1 is anelevation ofmy improved mechanism with the stationary `vbase plate or cover removed.

' Figure 2'is a section on line 2--2 of Figure 1.

Figure 3 is a fragmentary section ltaken on line 3--3 of Figure 1, and

Figures 4 and 5 illustrate certain details to be described hereinafter.

Like characters designate corresponding Aparts throughout the several views.

I `is the main Yor outer drum, pressed from sheet metal, having the lusual web 2 by which it is secured to the wheel of the the vehicle in any suitable manner well known in the art. 3 is the innerdrum, also lstamped from sheet metal, and

having the radial flange d by which it is secured to the inner face of the Web 2 by welding or other means. Y

in co-operative relation with the outer drum I are a pair of expanding brake shoes 5 of arcuate form, each of the said shoes consisting of a cylindrical flange 6 re-enforced by a central web "I and provided with laterally disposedlugs 9 at vtheir ends and center, respectively, the Whole being formed of sheet metal, preferably by stamping, or stamping and welding combined.

(Cl. 18S-78) Upon the outer periphery of the shoes 5 are mounted the brake blocks Il), of molded asbestos or other material having a high friction coei'licient, the said blocks being secured to the anges G by screws II which pass therethrough and are 5 screwed into nut members I2 which are imbedded in the blocks. The blocks I0 are also provided with transverse projections I3 which engage in recesses I4, thereby locking the parts securely against relative displacement in a rotary sense. l0

In co-operative relation with the inner drum 3 are a pair of contracting brake shoes I5 of arcuate form, each of the said shoes consisting of a cylindrical flange I6 re-enforced by a central web Il and provided with laterally disposed lugs l5 I8, IS at their ends and center, respectively, the Whole being Iformed preferably from sheet metal in a similar manner to that above described with regard to the expanding shoes 5.

Upon the inner periphery of the shoes I5 are 20 mounted the brake blocks 2i), also of molded asbestos or other material, the said blocks being secured to the ilanges I6 by screws 2| which pass therethrough and are screwed into nut members 22 which are imbedded in the blocks. The blocks 25 2G are also provided with transverse projections 23 which engage in recesses 24, thereby locking the parts securely against relative displacement in a rotary sense.

At diametrically opposed points are the anchor 30 members 25, the ends of which are secured in the stationary kplate 2S, the said plate being provided with re-inforcements 21 attached thereto by welding. These anchor members engage slidably in transverse slots 28, 29, formed in the 35 central lugs 9, i9, respectively, of the inner and outer brake shoes, there being interposed liners 30, 3l adapted to take up wear between the parts and to provide a larger bearing surface.

Rigidly secured to the stationary plate 2S are 40 the studs 32, and upon these studs are rotatably mounted rocker members 33, 34, arranged in pairs as shown in Figure 1, each pair being rotatably connected through the gear teeth 35. Each of the rocker members 33, 34 is connected 45 at its outer end to the brake shoes 6 by the tog.- gle links 36 and at its inner end to the brake shoes i5 by toggle links 3l. Each of the links 35 consists of a relatively thick web member provided at its ends with parallel cylindrical 50 heads adapted to engage in the corresponding transverse openings in the ends of the shoes I5 and in the rocker members 33, 34%. Each of the toggle links 31 consists of a relatively thin web member provided at its ends with parallel cylin- 55 drical heads adapted to engage in corresponding transverse openings in the ends of the shoes I5 and in the rocker members 33, 34.

Upon the rocker members 33, and preferably integral therewith, are the operating levers 38, 3S, the lever 38. being connected to the usual hook lever by means of the cable 40 and the yoke 4I, the latter engaging a pin 42 in the lever. To the pin 42 is also connected a yoke 43 which is connected to the lever 39 by means of the steel wire cable 44 and yoke 45, the latter engaging a pin 45 in the lever. The cable 44 Apasses around a pair of sheaves 41, 48 and is kept taut by the helical tension spring 49, one end of which engages at 50 in the yoke 45 while the other end is anchored at 5| by means of the link 52.

It will be observed from the foregoing description and by reference to the drawing that when the cable 40 is pulled in the direction of the arrow 53 through the usual foot-operated mechanism, the levers 38, 39 will be moved in a direction indicated by the respective arrows 54, 55, and by thisV movement and consequent rotary movement of the rocker members 33, 34, the outer brake shoes 5 will be expanded and brought into frictional engagement with the outer drum I, while at the same time the inner brake shoes I5 will be contracted and brought into frictional engagement with the inner brake drum 3, thereby producing simultaneously, four separate and distinct brakingr effects, which are at the same time in balanced relation as regards the internal forces. It will be observed that the toggle members 35 are under a compressive stress when in action, whileV the toggle members 31 are under tensional stress.

It will be noted also that where the respective toggle links engage in the webs 1 and I 'I, and also in the lugs 8 and I8, bushings are provided s0 as-to increase the wearing surface at these points.

in the rocker members 33, 34 and in the ends of the shoes 5 and I5 are formed with one solid end, as indicated at 56 in Figure 4, the other end being open for the introduction of the toggles, after which introduction they are closed by means of the washers 5l which may be fiber, felt or other suitable material.

The brake blocks I0 and 20, as will be observed by reference to Figure 1, are made of considerably greater thickness at their middle than at their ends, by which construction the wear upon the blocks is equalized and the blocks themselves can be kept in continuous operation practically throughout their wholelife without adjustment of any kind and, due to the distribution of the pressure throughout their whole peripheral surface and the consequent equality of wear of the material as well as of the dissipation of the heat resulting from the necessary friction,

the life of the blocks will be many times that of those of the type at present employed.

In order to compensate for any stretch in the cable 44, the stud 58, upon which the'sheave 48 is mounted, is formed with anA eccentric portion In order to retain the toggleV Ylinks in place, the openings for their reception 60, shown in Figures 1 and 5, which is capable of being adjusted throughout the length of the slot BI in the plate 26.

It will be understood from the foregoing that I have provided a brake which is of so power- 5 ful construction as to be capable of satisfactory operation under the heaviest loads, as well as under the most exacting conditions of service, without excessive heating and wear, and which maybe operated over long periods without any 10 attention or adjustment, and while I have herein described and sho-wn a preferred embodiment of my invention, it will be readily understood by those skilled in the art that the same may be modified in various ways to meet any parl5 ticular or peculiar requirement, without departing from the spirit of my invention. For eX- ample, while I have hitherto referred to-my improved brake as comprising inner and outer brake shoes combined and arranged for simulta- 2G neous operation, I may, in cases where conditions require a brake of reduced power, employ either the outer or inner set of shoes and operating mechanism alone, so that the same component parts can be used for light or heavy 25 vehicles and the cost of the said parts thereby greatly reduced, due to the increased volume of production.

Having thus described my said invention, what v I claim and desire tov secure by Letters Patent 30 of the United States is:

l. A brake for motor-driven vehicles comprising concentric inner and outer drums having a space therebetween, a stationary anchor plate forming a closure for said space, a pair of diametrically opposed brake shoes slidably mounted upon said plate and adapted for frictional engagement with the internal periphery of said outer drum, a pair of similar shoes slidably mounted upon said plate and adaptedl for fric- 40 tional engagement with the external periphery of said inner drum, pairs of rocker members pivotally mounted upon said plate and geared together for simultaneous movement in opposite directions, toggle links connecting said rocker 45 members to the opposed ends of each pair of said shoes, and operating means connected to one of each pair of rocker members whereby both pairs of said shoes are simultaneously brought into frictional engagement with their 50 respective drums throughout their periphery. 2. A brake for motor-driven vehicles comprising concentric inner and outer drums having a space therebetween, a stationary anchor plate@ forming a closure for said space, a pair of diametrically opposed brake shoes slidably mounted upon said plate and adapted for frictional engagement with the internal periphery of said outer drum, a pair of similar shoes slidably-i mounted upon said plate and adapted for fric- 60 tional engagement with the external periphery of said inner drum, pairs of rocker members pivotally mounted upon said plate and geared together for simultaneous movement in opposite directions, toggle linksV connecting said rocker members to the opposed ends of each pair of said shoes, and operating means connected to one of each pair of rocker members whereby both pairs of said shoes are simultaneously brought into frictional engagement with their'70 respective drums throughout their periphery, said operating means comprising lever arms upon said respective rocker members and a flexible member connecting said lever arms to a brake, pedal and to each other.

3. A brake for motor-driven vehicles comprising concentric inner and outer drums having a space therebetween, a stationary anchor plate forming a closure for said space, a pair of diametrically opposed brake shoes slidably mounted upon said plate and adapted for frictional engagement with the internal periphery of said outer drum, a pair of similar shoes slidably mounted upon said plate and adapted for frictional engagement with the external periphery of said inner drum, pairs of rocker members pivotally mounted upon said plate and geared together for simultaneous movement in opposite directions, toggle links connecting said rocker members to the opposed ends of each pair of said shoes, and operating means connected to one of each pair of rocker members whereby both pairs of said shoes are simultaneously brought into firctional engagement with their respective drums throughout their periphery, said operating means comprising lever arms upon said respective rocker members, a flexible member connecting said lever arms to a brake pedal and to each other, and a pair of guide sheaves for said flexible member, one of said sheaves being eccentrically adjustable.

4. A brake for motor-driven vehicles comprising a drum, a stationary anchor plate, a pair of diametrically opposed brake shoes slidably mounted upon said plate and having their ends spaced apart, pairs of rocker members pivotally mounted upon said plate between adjacent ends of said shoes and geared together for simultaneous movement in opposite directions, flat toggle links having cylindrical heads engaging in complementary cylindrical openings in the adjacent faces of said brake shoes and said rocker members, and operating means connected to one of each pair of rocker members whereby both of said shoes are simultaneously brought into frictional engagement with said drum throughout their periphery.

5. A brake for motor-driven vehicles comprising a drum, a stationary anchor plate, a pair of diametrically opposed brake shoes slidably 5 mounted upon said plate and having their ends spaced apart, each of said shoes consisting of a cylindrical flange re-enforced by a central web and provided with laterally disposed lugs at its ends, pairs of rocker members pivotally mounted upon said plate between adjacent ends of said shoes and geared together for simultaneous movement in opposite directions, toggle links having cylindrical heads engaging in complementary cylindrical openings in said rocker members and in transverse tubular bushings secured to the flanges and lugs in the ends of said shoes, and operating means connected to one of each pair of rocker members whereby both of said shoes are simultaneously brought into frictional engagement with said drum throughout their periphery. Y

6. A brake for motor-driven vehicles comprising a drum, a stationary anchor plate, a pair of diametrically opposed brake shoes slidably mounted upon said plate, pairs of rocker members pivotally mounted upon said plate and geared together for simultaneous movement in opposite directions, toggle links connecting said rocker members to the opposed ends of said shoes, operating means connected to one of each pair of rocker members whereby both of said shoes are simultaneously brought into frictional engagement with said drum throughout their periphery, arcuate friction elements upon said shoes having a greater thickness at their middle than at their ends, and means for securing said friction elements to said shoes comprising nuts embedded within said elements and screws passing through said shoes and engaging said nuts.

ALFRED C. ADAMS. 

